For me the real question is just how much it's Linux under the hood. And how many packages will be available. In Android the entire Linux userland was thrown out of the window by design. You can install busybox and get some basic things working but anything more complex - forget about it. Go to Google Play and buy some stupid game or something... On newer version of Android the situation is a bit better but I got 2.3.5 and it's really, really ugly. So who needs more than one pathetic excuse for an operating system that can only run junk? (And we already have more than one.)
I have a feeling that Ubuntu Phone will end up being the same. There's still hope that I'm wrong though. Time will tell.
Maybe throwing away "ecosystem" helped Android success? Maybe SurfaceFlinger and AudioFlinger are more suitable for phones than their "ecosystem" counterparts?
Google's official story about Android shortcomings is that they had to push release very fast and that some of needs were not meet in Linux kernel.They also needed to be as abstract from underlying layer as possible that's why people often don't call Android Linux.But no matter how simmilar Linux official(vanila) kernel is to Google's it's never going to be as compatible or liberating as uPhone,Firefox OS or Sailfish.